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Full Otocinclus Care Guide for Beginners

Full Otocinclus Care Guide for Beginners

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This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addition, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

Otocinclus catfish are great fish to own for many reasons. They’re bottom-feeding fish that are going to work well in your tank as cleaners.

These fish work to keep the plants in your fish tank clean and they’ll also clean the glass. To add to this, many people love putting otos in community fish tanks.

You might be thinking of getting these fish sometime soon. Before you do, it’s best to learn all that you can about caring for them.

Below, you’ll learn everything you need to know about otocinclus care. This will ensure that you can care for otos to the best of your ability.

There Are Many Types of Otos

Before moving further, it’s important to know that there are many types of otos out there. There are twenty-two known otocinclus catfish species at this time.

The general care requirements for otos are similar no matter what. The big differences between the otos involve the size of the fish and the appearance of the fish.

Common otos are the typical fish that you find being sold in pet stores. These fish have fins that are close to transparent, brown speckled upper bodies, and white lower bodies.

Golden otos have golden bodies but otherwise, look similar to common otos. Zebra otos are known for having zebra-like markings.

Giant otos grow to be up to four inches long. There are many types of otos that come in different colors and look a bit different than usual.

If you find yourself drawn to otos, you can seek out some of the more exotic colorations if you want to. Below, you’ll learn about caring for common otos so you can know what to expect when keeping these fish in your tank.


Getting the temperature right is very important when caring for any fish. You need to keep the temperature in the right range so the otos can remain healthy.

Otos do best in temperatures that range from 72 degrees Fahrenheit to 82 degrees Fahrenheit. Make sure that you use a heater and keep an eye on the temperature.

You should have a thermometer in the tank so you can easily see the water temperature at a glance. This is common advice that you should keep in mind when caring for any fish.


The pH balance level is always incredibly important when caring for fish. If the pH balance is out of the right range, the fish can easily get sick and die.

Thankfully, otos can tolerate a fairly wide range of pH balance levels. They do nicely in pH balances that range from 6.0 and 7.5.

However, it’s best to note that these fish do best when the pH balance is stable. If the pH level fluctuates wildly, this could easily stress the fish.

Keep monitoring the pH balance of the tank by testing it regularly. Most experts recommend testing the pH balance using a testing kit every two weeks.

You could probably get away with testing monthly, but it’s often best to err on the side of caution. Keep the tank clean and do regular water changes to keep the pH balance where it needs to be.

Water Parameters

Keeping the water parameters where they need to be for otos should be too tough. You must keep the water temperature between 72 degrees Fahrenheit and 82 degrees Fahrenheit.

Be sure to use a heater that will work for the tank size that you have. You want the temperature to remain stable because fluctuations can stress the fish.

It’s also true that pH balance fluctuations can stress the fish. Keep the pH balance between 6.0 and 7.5 while trying to keep it fairly stable.

To keep the water quality high, it’ll be necessary to buy a good filter. You need a mature filter that can cycle the water four times per hour.

The ammonia and nitrite levels should never be measurable in the tank. Nitrate levels must remain between 0 and 20 ppm.

The Habitat

In nature, these fish can be found in South America. They swim in schools and live in small rivers.

The small rivers that they inhabit are highly oxygenated and the streams flow slowly. It’s best to replicate these conditions in the fish tank.

You need to provide these fish with the right substrate material, decorations, and plants to make them feel at home. The best substrate material for otos will be some type of soft fine-grained sand.

These fish also love spending time in little caves and driftwood. It’s recommended to add caves, driftwood, rocks, and plants to the tank.

Decorations such as this will encourage algae growth and that helps the otos. It also gives them places where they can hide when they feel the need.

Most people choose to use standard aquarium lighting when caring for these fish. You don’t necessarily need to use special lighting to make algae grow faster.

It’s fine to just place the tank in a position where direct sunlight will hit it daily. Also, be sure to feed your otos enough food and it’ll naturally help algae to grow in the tank.

The Substrate

As mentioned above, it’s best to choose some type of fine-grained sand as the substrate material for these fish. You want the sand to be soft so it doesn’t hurt the fish in any way.

These bottom-feeding fish will be spending a lot of time at the bottom of the tank. They like to dig through the substrate material, and it’s easy for them to get hurt by coarse substrate materials.

Choosing fine-grained aquarium sand will keep the fish safe. You can easily find what you need at a pet store or an aquarium store.

It should be easy enough to get the right substrate and keep your otos happy. They’ll spend a lot of time near the substrate so this is an important aspect of setting up the tank for these fish.

Otocinclus Bioload

Adding otocinclus catfish to the fish tank won’t add much to the bioload of the tank. They’re cleaners and they’re going to help the tank quite a bit.

Even so, it’s best not to overload the tank. Ensure that you have enough room for otos before you put any in the aquarium.

Do Otocinclus Need a Filter?

It’s imperative to use a filter when caring for otocinclus catfish. These fish won’t do very well if the water quality dips.

You must use a powerful filter that is capable of cycling the water four times per hour. So you can’t just buy a weak filter and hope that all will be well.

These fish live in highly-oxygenated water in the wild. They need the same conditions to thrive in your fish tank.

Do your best to buy a high-quality filter that will work for the fish tank size that you’re using. Doing so should help you to keep the otos in good shape.

Do Otocinclus Like Current?

Strong currents won’t be good for these fish. In the wild, they can be found in slow-moving rivers.

You want the water flow to be modest without being overpowering. The flow can be mitigated by putting plants and decorations in the fish tank.

So you must ensure that these fish are kept in a planted aquarium. You’re going to be using a powerful filter, but the plants should help the current to not be too overpowering for the fish.

Plus, these fish simply love being able to hide among the plants. You should have all sorts of plants and caves in the tank for these fish to use.

Do Otocinclus Need Driftwood?

You don’t have to put driftwood in the tank for otos. These fish don’t require driftwood as many wood catfish do.

However, it can still be beneficial to put driftwood in the tank. It’s optional, but it’s something that can help them.

Driftwood can be useful in several ways. It can help the otos to have another source of food, and they can use it as a hiding spot.

It’s very common for people to put driftwood in the tank with otos. So feel free to do so if you’d like to.

Do Otocinclus Need Live Plants?

Yes, it’s best to keep otos in fish tanks that have live plants. These fish do best in planted aquariums because they like to graze on plants.

Also, the plants simply help them to feel more comfortable in the tank. You’ll find the otos hiding among the plants sometimes.

You should pick good plants for the otos that will work well for their needs. There are many great options that you can choose from, but many people start with simple plants such as java ferns.

Cabomba plants are highly recommended as well since they come close to the types of plants that otos graze on in the wild. Other plants that work nicely include anubias plants, jungle Val, dwarf lilies, and cryptocoryne plants.

Are Otocinclus Catfish Hardy?

These fish are hardy once they’ve acclimated to the tank. Until then, they can be a bit fragile.

It’s important to put them in a planted aquarium to give them the best shot. They acclimate best to planted aquariums with the best possible conditions that suit them.

Once the fish acclimate to the tank, they become very hardy. They should survive and do well in your tank for quite some time once they’re established.

Sadly, otos do sometimes die when being put in new tanks. They have particular dietary needs that can make it tough to get them to the point where they’ll acclimate to the new environment.

What Do Otocinclus Catfish Eat?

You already know that otocinclus catfish like to eat algae. They will also feed on plant matter and bacteria in the tank.

The best way to keep these fish in good shape in your aquarium is to ensure that they have enough algae. Do your best to expose the fish tank to direct sunlight so that algae will grow.

You can supplement the natural algae growth in the tank by feeding the fish algae rounds and wafers. It’s also common for people to feed these fish blanched veggies such as spinach, lettuce, and zucchini.

When feeding the fish veggies, only add small pieces of food to the tank once daily. Make sure to remove uneaten food from the tank after 24 hours have passed.

How Many Otos Should Be Kept in One Tank?

It isn’t good to keep just one or two otos in the fish tank. These fish like to swim in schools in the wild.

They won’t be comfortable in the tank if you keep too few of them. The minimum number of otos that you should put in a fish tank is six.

Many people like to keep up to ten of these fish in an aquarium. You must make sure that the fish have suitable conditions and that there’s enough algae for all of them to eat.

You might want to stick closer to six otos if you’re worried about not having enough algae to keep them healthy. Too many otos might devour the algae a bit too fast.

Otocinclus Catfish Are Peaceful and Shy

Before buying these fish, it’s important to recognize that they’re very peaceful and shy fish. They do work well in community fish tanks, but you need to be careful to choose appropriate tank mates.

Some aggressive types of fish might bully the otos. You also need to provide these fish with hiding spots in the tank so they can remain comfortable.

Without hiding spots, the otos will feel more vulnerable than usual. Many things can be used as hiding spots in a community aquarium.

Planted aquariums provide great hiding spots. The otos will commonly hide among the plants.

It’s also good to put little caves and rocks in the fish tank. You’ll see these fish using these hiding spots quite regularly.

Since these fish are so passive they’re going to do whatever they can to avoid conflict. The instinct of an otocinclus catfish is to hide rather than fight back.

Best Tank Size for Otos

Common otos should be kept in groups of six or more. You’ll need a minimum of a ten-gallon fish tank to keep these fish comfortable.

Many people choose to go with twenty-gallon fish tanks. You might wish to go larger than this if your goal is to keep them in a community tank.

Overcrowding the tank isn’t a good idea. When you cram too many fish in the tank, it leads to stress and it makes it harder to keep the fish tank clean.

How Big Do Otos Get?

Most otos are going to grow to be around two inches long. Common otos should grow to be two inches long and they can live for three to five years in captivity.

Other types of otos might grow to be a little larger. Giant otos are known to be four inches long at maturity.

To help your otos grow strong and stay healthy, ensure that they have a steady diet of algae and plant matter. Remember to supplement the diet of the fish with algae wafers and blanched veggies as necessary.

If you continue to care for these fish well, they will grow and thrive in your tank. It’s necessary to look after them and do regular tank maintenance to keep them from getting sick, too.

Are Otocinclus Good for Beginners?

Otocinclus catfish should be decent options for beginners. However, you must remember that these fish will sometimes die when being added to a new tank.

You have to be careful to get the conditions right and feed these fish properly. Otherwise, they won’t acclimate to the tank.

So it does require a bit of effort and attention. They might not be the easiest fish for beginners because of this, but they’re still low-maintenance fish once they’ve acclimated to the tank.

Ensure that the fish have access to algae and that the conditions are right. If you can handle this, the fish will thrive and remain healthy in your aquarium.

Tank Maintenance Tips

Tank maintenance is very important when caring for these fish. It’s true that the otos themselves will help to keep the tank clean, but you need to do regular water changes as well.

The water needs to be oxygenated properly, and you can’t let the ammonia, nitrate, or nitrite levels rise in the tank. Regular water changes help to keep the water clean and safe for your fish.

It’s recommended to change the water weekly. Do 30% water changes each week and you should have an easy time keeping the tank clean and safe.

Final Thoughts

Knowing how to take care of otocinclus catfish will give you a great experience. These fish are hardy once they have acclimated to a tank.

You can have a simple time keeping these fish in your tank so long as you keep an eye on the water parameters. Keep the temperature and the pH balance in the right range for these fish.

Otos need to have a plentiful source of algae so they can remain healthy. Put the fish tank in direct sunlight so that algae growth will be encouraged.

Be sure to put these fish in groups of six or more. They don’t do well in smaller groups.

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